Browse Prior Art Database

Heat Pulse Detector

IP.com Disclosure Number: IPCOM000092029D
Original Publication Date: 1968-Aug-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Wigmore, JK: AUTHOR

Abstract

This heat pulse detector is capable of observing 100 nanosecond long heat pulses in magnetic fields up to at least 30 kilo oersteds. The detector combines the sensitivity and rapid response of a superconducting bolometer with the magnetic field insensitivity of carbon resistor films. The detector comprises small chip 1 of extrinsic semiconductor material, e.g., N-type germanium, N-type silicon. Metal, e.g., gold-antimony, lands 2 and 3 are evaporated on chip 1 and provide contacts for leads 4 and 5 that are connected to current measuring unit 6. Chip 1 is bonded, using an epoxy resin 7, to face 8 of crystal 9, such face being polished optically flat. From an external power supply, not shown, chip 1 is biased to the onset of avalanching, about 1 volt/cm for N-germanium.

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Heat Pulse Detector

This heat pulse detector is capable of observing 100 nanosecond long heat pulses in magnetic fields up to at least 30 kilo oersteds. The detector combines the sensitivity and rapid response of a superconducting bolometer with the magnetic field insensitivity of carbon resistor films. The detector comprises small chip 1 of extrinsic semiconductor material, e.g., N-type germanium, N-type silicon. Metal, e.g., gold-antimony, lands 2 and 3 are evaporated on chip 1 and provide contacts for leads 4 and 5 that are connected to current measuring unit
6. Chip 1 is bonded, using an epoxy resin 7, to face 8 of crystal 9, such face being polished optically flat. From an external power supply, not shown, chip 1 is biased to the onset of avalanching, about 1 volt/cm for N-germanium. Crystal 9 is MgO:Fe/++/ and is about 7 millimeters long. On face 10, parallel to face 8, is evaporated thin film 11 of Constantan, an alloy of nickel and copper, on to which are deposited indium leads 12. Electrical pulses, 1/10 microsecond in duration, are sent through leads 12 so as to generate a heat pulse from film 11.

The heat pulse passing through crystal 9 excites electrons from the donor ground state of the germanium into the conduction band, according to the Boltzmann factor, thus increasing the electrical current through the semiconductor sensing device. Each electron thus excited impact ionizes many other impurities giving rise to an amplification of the original curr...